A nutrient increment method for reducing bias in global biogeochemical models

摘要: [1] Assimilation of physical variables into coupled physical/biogeochemical models poses considerable difficulties. One problem is that data assimilation can break relationships between and biological variables. As a consequence, tracers, especially nutrients, are incorrectly displaced in the vertical, resulting unrealistic biogeochemical fields. To prevent this, we present idea applying an increment to nutrient field within assimilating model ensure nutrient-potential density maintained water column during assimilation. After correcting it assumed other rapidly adjust corrected We applied this method 17 year run 2° NEMO ocean-ice PlankTOM5 ecosystem model. Results were compared with control no assimilation, but increment. In incrementing experiment, phosphate distributions improved both at high latitudes equator. At midlatitudes, generated advective upwelling nutrients boundary currents, which spread subtropical gyres more biased This result was largely unaffected by probably due currents being poorly resolved Changes fed through parameters altering primary production, air-sea CO2 flux, chlorophyll distributions. These secondary changes most pronounced equator, limited than latitudes.